On Wed, Feb 02, 2022 at 01:12:54PM -0500, Peter Cai wrote:
> Mirroring commit 97ab802aa36f ("adc: meson-saradc: add support for
> getting reference voltage value") for meson-saradc, this adds support
> for getting the "vref-supply" regulator and register it as the ADC's
> reference voltage regulator, so clients can translate sampled ADC values
> to voltage.
>
> Signed-off-by: Peter Cai <pe...@typeblog.net>
> Cc: Simon Glass <s...@chromium.org>
> Cc: Philipp Tomsich <philipp.toms...@vrull.eu>
> Cc: Kever Yang <kever.y...@rock-chips.com>
One code style nit below, but:
Reviewed-by: John Keeping <j...@metanate.com>
Tested-by: John Keeping <j...@metanate.com>
The results from this look good on RK3288.
> ---
> drivers/adc/rockchip-saradc.c | 21 +++++++++++++++++++++
> 1 file changed, 21 insertions(+)
>
> diff --git a/drivers/adc/rockchip-saradc.c b/drivers/adc/rockchip-saradc.c
> index e464d33f2267..67c11d896e8d 100644
> --- a/drivers/adc/rockchip-saradc.c
> +++ b/drivers/adc/rockchip-saradc.c
> @@ -13,6 +13,7 @@
> #include <asm/io.h>
> #include <linux/bitops.h>
> #include <linux/err.h>
> +#include <power/regulator.h>
>
> #define SARADC_CTRL_CHN_MASK GENMASK(2, 0)
> #define SARADC_CTRL_POWER_CTRL BIT(3)
> @@ -100,8 +101,11 @@ int rockchip_saradc_stop(struct udevice *dev)
>
> int rockchip_saradc_probe(struct udevice *dev)
> {
> + struct adc_uclass_plat *uc_pdata = dev_get_uclass_plat(dev);
> struct rockchip_saradc_priv *priv = dev_get_priv(dev);
> struct clk clk;
> + struct udevice *vref;
Should vref be above clk to keep the reverse Christmas tree order of
decreasing line length?
> + int vref_uv;
> int ret;
>
> ret = clk_get_by_index(dev, 0, &clk);
> @@ -114,6 +118,23 @@ int rockchip_saradc_probe(struct udevice *dev)
>
> priv->active_channel = -1;
>
> + ret = device_get_supply_regulator(dev, "vref-supply", &vref);
> + if (ret) {
> + printf("can't get vref-supply: %d\n", ret);
> + return ret;
> + }
> +
> + vref_uv = regulator_get_value(vref);
> + if (vref_uv < 0) {
> + printf("can't get vref-supply value: %d\n", vref_uv);
> + return vref_uv;
> + }
> +
> + /* VDD supplied by common vref pin */
> + uc_pdata->vdd_supply = vref;
> + uc_pdata->vdd_microvolts = vref_uv;
> + uc_pdata->vss_microvolts = 0;
> +
> return 0;
> }
>
> --
> 2.35.0
>
